Machine tool



April 2, 1946. K, RAUCH 2,397,504

MACHINE TOOL v Filed April 14, 1944 3 Sheets-sheet 1 IN VENTOR.

ATTORNEY.

'K. RAUCH MACHINE TOOL April 2, 1946.

3 Sheets-Sheet 2 Fld April 14, 1944 A TTORNEY.

April A2,

K RAuH MACHINE T001.

Filed April 14, 1944 3 Sheets-Sheet 5 DIL PUMP MTUB WHEELIIEA D CEUs/IERMOTDB Pz Pm lo o/ololo IloIo I@ uw' am BY MM J na ATTORNEY.

- Patented Apr. 2, 1946 MACHINE TOOL Konrad Rauch, Dayton, Ohio,assigner to The.

Sheield Corporation, Dayton, Ohio, a corporation of Ohio ApplicationApril 14, 1944, Serial No. 530,985

4 Claims.

This invention relates to machine tools and more particularly to threadgrinding machines and the like in which a carriage such as a workholding table is arranged for feeding movement in either of' a pluralityof directions. One object of the invention is the provision of `amachine tool having a carriage feed for driving the carriage in aselected direction according to the manner in which power transmissiongears are arranged, with controlling stops to determine the extent offeeding movement, together with a plurality of control members,associated through a lost motion connection, for

starting and stopping the carriage movements` and controlling switchesin such a manner that one or the other of the stops causes movement ofoneor both ci the switch control members to stop the feeding or returntraversing movement oi the carriage irrespective of the direction inwhich the carriage is traveling..

Another object is the provision cf a machine tool having control meansof the character men-n tioned, the two control members being arrangedfor movement in either direction from normal and determining thedirection in which the feeding movement of the carriage takes place,each of the two control members having a switch ineluded in thecontrolling circuit so that operation of either of the controllingswitches, by one or the other of the two controlling members, will stopthe feeding or traversing movement of the carriage.

Another object of the invention is to provide a convenient and practicalcontrol and switch arrangement for a motor driven traversing mechanismof the work holding carriage of a grinding machine, so arranged that acontrolling lever may be moved from its normal position towards theright or the left to determine the direction of carriagefeed andcooperate with stops on the carriage regardless of the direction inwhich the carriage is moving, to electrically disconnect the carriagedrive.

Other objects and advantages of the invention ywill be apparent from thefollowing description` the appended claims, and the accompanyingdrawings, in which,

Fig. l is a perspective view of a grinding machine embodying the presentinvention;

Fig. 2 is a perspective diagrammatic showing of the driving mechanismfor rotating the work and for feeding and traversing the carriage onwhich the work is supported;

Fig 3 is a perspective view showing the two feed controlling members oneof which is arranged for manual operation while the other is controlledautomatically to stop the feeding or traversing movements oi thecarriage;

Fig. 4 is a side elevation, partly in section, showing the controllingmembers and their association with the stops on the carriage:

Fig. 5 is a diagrammatic view showing the electrical connections or thevarious parts; and

Fig. 61s a diagrammatic showing the switch connections for manualcontrol.

Referring more' particularly to the drawings, in which the samereference numerals have been applied to like parts in the differentviews, it

generally designates the base oi a thread grinding machine whichincorporates a motor driven grinding wheel li arrangedl on a wheel slidel2 which can be moved on the base towards and from the work axis. 4'Thebase also supports the work holding carriage 83 which can travel towardsthe right or left as viewed in Fig. l. This carriage has a tail stock Mand a live center it. In the driving head it is suitable transmissionmechanism, drivenby the work-head motor ll, for rotating the center l5and for turning a lead screw which operates in a nut on the carriage to`cause feeding and traversing movements or the carriage. The machine, ingeneral. is or the character shown in Patent 2,060,433, granted Novemberl0, 1936, insofar as the arrangement or the mentioned parts isconcerned.

The driving mechanism in the work-head it is illustrated in Fig. 2. VThework motor il drives a vertical shaft i9 having a worm 'itl which turnsworm wheel 2l and thus rotates worms 22 and 23. The worm 23 drives theworm gear 2t, shaft 25, and gear 2o meshing with gear 2l. 'The latter ison a Shaft 2t having a worm 2@ which meshes with worm gear St. Thelatter rotates freely on a spllned shaft @il and is provided with aclutch face adapted to be engaged by a clutch disc fici which is splinedon the shaft t2. When the clutch disc to and clutch face 38 are engaged,the Worm'wheel Si@ rotates the spline shaft 3'2 comparatively slowly,calming corre-- sponding rotational movements of a spur gear @t fixed onthe endI oi the spline'shaft. Gear S5 meshes with a driving gear t@fixed on the driving spindle 3l in which the live center 05 is provided.The work 3S is thus driven in the direction of the arrow atcomparatively low speed orrotation. for feed movement.

During feed movement, the clutch disc 34 is held over against the clutchface 33 by a thrust toward the right as viewed in Fig. 2 on the hel- 5ical gear 39 created by the pressure of gear 22 when the latter turns ina clockwise direction as viewed in that figure. This pressure holds thegear 3S against a collar lili interposed between that gear and theclutch disc 3G, collar iii and gear 39 being freely rotatable on thesplined shaft 32.

When the direction ci rotation of shaft U9 is reversed, the gear 22turns in a counter-clockwise direction and moves the slidable gear 89towards the left to permit disengagement of the clutch disc 3Q which hasa dried axial spacing trom a clutch disc t l, and to cause drivingengagement or" clutch disc di, iixed to gear 3Q, with the clutch race i2on a gear i3 which is splined on the shaft 32. Under these conditionsthe splined shaft it is rotated at a comparatively high speed in adirection opposite to that shown by the arrows, causing correspondingrotation of the gear 35 and thus rotating the work rapidly in a reversedirection. This high speed rotation ci the work taires place during arapid traverse or' the work supporting carriage, and the low speedoperation or the work is produced during the comparatively slow feedingmovement ci the carriage in a selected direction, towards the right orleft. The feeding and traversing mechanism :for carriage i3 is drivenfrom gear it which turns with the spline-d shaft 32 in one direction orthe other.

The gear it is connected through gears dll, (l5, 46, 4l, ad, 43 and t@to the feed screw 52 which is rotatably supported in suitable bearingson the machine base. The reed screw turns in a stationary nut 52% whichis held on the work supporting carriage it. li the nut is turned to alimited extent an accurate adjustment may be made in the position of thecarriage, but during feeding movements ci the carriage the nut issubstantially fixed.

With one idler 'gear el interposed between the gears 46 and 48 thedirection of rotation ot the feed screw 52 will be opposite to thedirection in which the spline shaft 32 turns. By adding a second idlergear between gears it and (il, as by swinging the carrying plate d to alowered position, the feed screw t2 may be caused to turn in the samedirection as spline shaft t2. .es the work rotates in a given directionyit will thus be obvious that either right hand or left hand reedingmovements of the work supporting carriage can be obtained dependent onwhether one or two idler gears are interposed between the gears 46 and48. .As the gear 43 is splined on the shaft 32 and operates atcomparatively high speed in one direction and at comparatively low speedin the other direction according to which one oi the two drivingclutches is engaged, it will be seen that a, comparatively slow speedfeeding movement may be given to the worlr carriage in either a. righthand or a left hand direction, and a comparatively rapid traversingreturn will then take place in the opposite direction.

The grinding wheel may be moved manually towards the work axis by upwardmovement of an arm 56 into the position shown in Fig. 4. lin thisposition it closes a switch 51 and opens a switch 63 which will bepresently described. A latch arm 58 iixed to a handle 59 and yieldinglyurged in a clockwise direction by a spring 60 and a spring pressed pin6I serves to latch arm 56 in its raised position. By raising the arm 5Sa. threaded shaft 62 on which the ami is fixed is rotated against theaction of a spring, not shown, and the slide that carries the grindingwheel is positively drawn towards the work and into a predeterminedposition. When the latch arm 58 releases arm 56 the acentos spring whichoperates on the shaft 62 turns the latter, and moves the arm 56 baci: toits initial position which retracts the grinding wheel slide away fromthe work. Counter-clockwise movements of the latch arm VdS are causedmanually, or automatically by a com di adjustably secured on the worlccarriage i3. When the com i reaches a vertically slidable pin @t whichis held in engagement with the upper side of arm t9, it presses thelatter downwardly against the action of spring Sii and releases thelever 5B.

v The motor il, which operates the eed screw and turns the worlr, iscontrolled by switches that are actuated manually and automatically bycontrol arms 8l and @il plvotally carried and indeendently movable on ashaft '59 that supports the latch arm with its handle Arm Cil is xed tothe hub portion il@ and a lever li which carries a roller i2 arranged todepress either one or the other of two spring pressed pins iii and 'ddcontrolling start switches i5 and 'it respectively. These switches arenormally own, but one or the other is closed according 'to the directionin which the arm (il is turned from its lyieldingly center the arm et.

normal upright position.

The arm (id is also pivotally movable on the shaft @il and can be movedindependently oi arm @il through a limited distance determined by a lostmotion connection between these two arms. This connection comprises a'pin ll on the arm @8, projecting into a recess i8 in the huh portionlil of arm tl. The width of this recess i8 is such that arm oil can bemoved ier enough to depress the pin i3 or l@ while still leaving somesmall clearance between the pin ll and the adjacent portion or the hubiii. Fixed on the arm lit are two side arms @El and Si which bearagainst spring pressed pluri-gers 82 and which oct to 'These plungersoperate micrometric or precision switches 'it' and l5 respectively, theswitches being normally closed when arm til is its normal uprightposition. However, as soon as the arm td is moved even through afractional part or" a degree, one or the other or" these switches willbe opened, clockwise movement of the arm to, for example, opening theswitch l5 without affecting switch l'.

The arm 53 is automatically moved by stops 85 and Sii which are shown asthreaded screws adjustably mounted in carrying blocks 8l and 38 whichare adjustable along bars 39 fixed on the work carrying slide i3. As theslide moves towards the right or the left, one or the other of thesestops t5, to comes into contact with a rearwardly extending pin do fixedon the arm 68 and projecting into the path of movement of the stops, thestop which is effective thus producing, to a limited degree, a turningmovement of the arm t8 and opening the switch l5 or i8. One or the otherof these switches is in the motor energizing circuit, under normalconditions. Under abnormal conditions, where the switch that is openedby the stop on the carriage may not be the switch that c'ontrols thestopping of the work feeding or traversing motor, any continued movementof the arm 68 under the impelling movement of the stop swings the arm 68still further, and brings the pin 71 against the side of the recess inarm 6l, thus positively swinging the arm 6l which had been displacedtowards that stop by the operator in initiating the carriage movements.'I'he arm 61 is thus moved back to its normal position and opens theswitch l5 or 'I6 that had been closed by this arm 6l.

The'switch 15 is in series with the switch 15' censos as will beapparent from Fig. 5, and switch 18 is in series with switch 16'. Toinitiate right hand feeding movement of the carriage, as in cutting aright hand thread, the arm 81 is moved towards the right from its normalposition as viewed in Fig. 3, causing the switch 15 to close. This willproduce slow rotation of the work in the direction of the arrow shown`in Fig. 2, only the one idler gear 41 being interposed between gears 48and 48 as indicated in Fig. 2. Movement oi' this arm 61 does not changethe position of the arm 08 which remains in a centered position so thatboth switches 16 and 15 are closed. The stop 05 will ultimately come upagainst the pin 90, the stop having been positioned so as to stop thefeeding movement at the proper time. Continued movement of the stoptowards the right will swing the arm 68 clockwise, or towards the rightas viewed in Fig. 3, pressing on the plunger 83 and opening the switch15 which is in series with the switch 15 energized at the time. Themotor energizing circuit is thus interrupted. The operator can thenswing the arm 61 towards the left and close the switch 16 to producerotation of the motor in the opposite direction, switch 16 being inseries with the switch 1B which at this time remains closed. As soon asthe carriage starts to travel toward the left, the stop 85 moves awayfrom pin 90 and permits the arrn 68 to center itself under the action ofthe spring pressed plungers 82 and 83.

Should the operator have applied two idler gears between the gears 46and 48 and then move the arm 61 towards the right, thinking he was goingto have a right hand movement of the carriage, the carriage wouldactually move towards the left. The stop 86, however, would be broughtup against the pin 90 and nrst tilt the arm 68 counterclockwise and openthe switch 16. This switch at this time is not in circuit, so thecarriage would continue its left hand movement and tilt the arm 88 stillfarther until the pin 11 comes up against the side oi the recess in thehub 'l0 and then the arm 61 would be positively moved back to itsupright position and openy the switch 'l5 which at this time is thecontrolling switch. Regardless of the direction of movements of thestops 85 and 86, the arm 68 or both the arms 61 and B8 will bepositively moved automatically in such a way as to open the switch whichis at that time the controlling switch in the motor energizing circuit,and it will be impossible for the stop to mechanically injure thecontrolling mechanism.

The operation described has been with reference to a right hand movementof the carriage. The operation of the lever or levers by the proper stopat the end of the rapid traverse of the carriage will be apparent. Toproduce a left hand feeding movement of the carriage, for cutting a lefthand thread, and with two idlers between the gears 46 and d8, the arm 61is manually moved towards the left, indicating the direction in whichthe carriage is to travel. In view of the symmetrical arrangement of theparts it will be apparent that the operation that takes piace is similarto that which has been described.

Referring more, particularly to the wiring diagram shown in Fig. 5, thevarious electrical connections will be explained, first in connectionwith an operation in which the machine is under the manual control ofthe operator to cut a right hand thread on the workpiece. Under theseconditions, the operator moves the control arm 61 towards the right,starting the feeding movements, and

then immediately pulls the arm 06 upwardly so as to bring the grindinglwheel into engagement with the work. At the end of the feedingmovement, determined by the stop 8l, this stop swings arm 88 towards theright to break the circuit of the motor that drives and feeds the work,and the cam 84 at the same time causes the arm 89 to be moved downwardlyagain. The operator may then move thearm 01 towards the left to rapidlyv traverse the carriage back to its initial position, where it will bestopped automatically by stop 86.

At the start of these operations, the operator sets a switch controllingknob 82, see Fig. l,l which adjusts a coolant motor switch 88 to close aconnection from wire 94 to wire 95, this setting providing a. continuousflow of'coolant from the coolant pump motor 06 after the machine startsoperation. The operator also adjusts a control knob 01 which aiects amaster switch 98 so as to connect either the wheel head motor 98 or asecond motor |00 in circuit. Motor |00 may drive the grinding wheel ata. slow rate of speed while truing the wheel. This operation of the knob91adiusts the contacts of master switch 98 into the several positionsshown in Fig. 6 so that the wheel head motor may be energized. Theoperator also turns ,knob |0| to the right hand feed manual controlposition, which affects master switch |02 so that its contacts will beadjusted to the positions shown in Fig. 6. He then presses the manualstart switch |06. When switch |06 is closed it starts an oil pump motori635 which is energized through connection |06 leading to one side of atransformer secondary |83. The other side of the secondary is connectedthrough wire |08 across the lower switch blades of master switch 98, towire |01, across closed switch iiit, closed stop switch |00, connectioniiii, through the oil pump motor |05 and back to the transformer throughconnection i055. The primary winding i i of the transformer mentioned isconnected to wires iii. and MS across one side of a three phase supplyline.

When the oil pump motor starts it builds up pressure in a pressureswitch i ifi which then closes so as to complete a controlling circuitextending from one side of the secondary iiiil through wire H5, switchenergizing coil iid, wire lil, across closed switch H4 to wire M0,through normally three switches of the master switch @d to vthe wheelhead motor 99, thus starting the grinding wheel.

The operator, having moved arm 56 upwardly to bring the wheel toward thework 'to a predetermined position, then swings the arm till towards theright, which closes switch l5, see Fig. 5, switches i5 and it remainingclosed. Switch i5 completes a control circuit through a switchenergizing coil 823 which closes the power switch IM and energizes thework head motor il so that it' will be driven in a forward direction androtate the shaft I9 in the direction indicated by the arrow shown inFig. 2. The circuit through the coil |23 is from the transformersecondary |03 through wire |08, master switch 88, wire lill, startswitch |04, connections |26, |21, down to switch 16', through wire |28to switch 15', across closed switch l5', through connection lit?,through closed switch llt, to wire i3d, then through connections Hdl, 32and through the coil i23, then through return circuit itt, wire i3d andback through wire [ld-5 to the trans former secondary. .At this point itshould be noted that either a movement oi control arm. Gl 'towards thelett, or bach to its norinal position,

or a movement or control arm. GG towards thev right will open thiscircuit between the connections @2l and lili and thus deenergiae theswitch controlling coil G23 so as to open the power switch ld.. K

The coolant pump motor @d will be energized under these conditions,since the power switch i3d that controls it will be closed by theenergication or winding lill connected through wire i3d to one side oithe transformer secondary and connected tlu'cughwires Q6, lill and idd.

After thev carriage has moved the worlr towards the right to apredetermined stopping position, the pin Si@ on arm 68 will be swung tothe right by the stop 85, thus opening switch lo and deenergizing therelay winding [|23 so as to open the power switch idd. The latch arm 5Swill be forced upwardly by the cam Gd and arm switches downwardly toretract the grinding wheel from the worlz.

The operator then initiates a rapid traversing return movement ci thecarriage by swinging the arrn oli towards the left which closes switchTIS. This completes a circuit 'through switch lli', which has remainedclosed, and through closed switch lli so as to energize a switchcontrolling coil id@ controlling the reversing power switch lill of theworlrhead motor il. The coil lll@ is connected to one side of thetransformer secondary Edil through 'wires lilo", i353 and i133. Thecircuit to the other side of the transformer is through connection llliacross a closed connection M3 through closed switch lli, connection Mld,closed switch it', connection tt', wire start switch ille, connectionslill and it@ to the other side of the transformer, The motor il is thusdriven in an opposite direction by the reversed phase relation producedby the connections to the power source when switch lill is energized,and the work holding carriage moves to the leit at a comparatively rapidrate of speed until the stop 86 moves the arm towards the left and opensthe switch lt', thus deenergizing the relay coil Mo and stopping themotor lll.

The motor il will be stopped at the end ci this rapid traverse eventhough the traverse tool; place in a right hand direction instead of aleit hand direction as intended, as might occur if the operator failedto provide proper gearing in the power transmission system. lf thecarriage moves to the right instead of `the left, arm @d through stop t5will be swung to the right and eventually swing arm 6l to the right soas to open switch "I6, after taking up the lost motion between these twoarms.

By suitable operation of the control knob lill the master switch |92 maybe set so that the work carriage automatically initiates a returntraverse movement at the end oi its normal feeding stroke. For thisoperation, circuits are manually closed across points M5 and acrosspoints Mii. At the end of the feeding stroke the arm 56 will swing downautomatically, closing the switch 63 so that winding 54B of the powerreversing switch IM will be energized through connection M2, switch 63instead oi switch M3, across closed connection M5, connection M4,

acentos closed switch l5', connection icl, start switch ltd andconnections icl and |08, thus energizing switch lill after deenerglzingthe switch |24.

While the form ci apparatus herein described constitutes a preferredembodiment oi the invention, it is to be understood that the inventionis not limited to the precise form herein described, and that changesmay be mode therein without departing from the scope oi the inventionwhich is dened in the appended claims.

What is claimed is:

l. ln a machine tool, a base, a carriage movn able thereon, carriageiced means including ad@ justable gearing for feeding the carriage in aselected direction, means lor driving said leed means, spaced stops onsaid carriage, a control member manually operable in one direction orthe other from a normal position, a pair of elec tric circuits forcontrolling the operation of said drive means, a pair ci switches onefor each ol said circuits and arranged lor selective operation accordingto the direction oi movement of said control member, a stop controlledmember hav ing a lost motion connection to said control member andmovable from a normal position'in one direction or the other, switchmeans selec tively operable according to the direction oi movement ofsaid stop controlled member, said switch means selectively controllingsaid circuits and so coordinated with said pair of switches that similarmovement or" said control member and stop controlled member in eitherdirection `irom normal Linder the control or said stops will defenergize the circuit controlling said drive means.

2. ln a machine tool, a base, a carriage movable thereon, carriage feedmeans including adjustable gearing for feeding the carriage in aselected direction, reversible means for driving said leed means, spacedstops-on said carriage, a control member manually operable in onedirection or the other from a normal position, a pair oi electriccircuits for controlling and reversing said drive means, a pair of startswitches one for each of said circuits and arranged for selectiveoperation according to the direction o movement oi till said controlmeans, a stop controlled member having a lost motion connection to saidcontrol member and movable from a normal position in one direction orthe other, switch means selectively operable according to the directionof movement of said stop controlled member, said switch meansrespectively having a series connection to the respective ones of saidswitches to selectively control said circuits so that similar movementof said control member and stop controlled member towards normalposition under the control of said stops will deenergise the circuitcontrolling said drive means, and movement of said stop controlledmember alone in the opposite direction will also deenergize the circuitcontrolling said drive means.

3. In a machine tool, a base, a carriage movable thereon, carriage feedmeans including adjustable gearing for `feeding the carriage in aselected direction, a reversible motor for operating said feed means,spaced stops on said carriage, a control lever operable in one directionor the other from a normal position, a pair of electric circuits forselecting the direction of operation of said motor, a pair of switchesone for each of said circuits and arranged for selective operation bysaid control lever, a stop controlled armhaving a lost motion connectionto said control lever and movable from a normal position in onedirection or the other, a second pair of switches, normally closed andselectively operable according to the direction of movement of said stopcontrolled arm, said second pair of switches selectively controllingsaid circuits and each connected in series with one of said first pairof switches so that movement of said stop controlled arm in onedirection under the control of one of said stops will deenergize thecircuit controlling said motor.

4. In a thread grinding machine having a base, a movable work carriageand carriage feed means having provision for reversing the direction ofcarriage feed, an electric motor for operating said feed means, spacedstops on said carriage, a manually controlled lever operable from anormal position in clockwise and counterclockwise directions, a pair ofelectric circuits controlling the operation of said motor, a pair ofswitches selectively energized according to the direction of movement ofsaid lever, said switches selectively controlling said circuits. anautomatically operable arm having a lost' motion connection to saidlever such that normal manual operation of the lever is without eiect onsaid arm, said arm being movable from a normal position in one directionor the other by said stops, a pair of switches selectively operable bysaid arm according to the direction of arm movement, one arm controlledswitch controlled by movement of the arm in one direction having aseries connection with the switch controlled by lever movements in theopposite direction to insure feed stoppage regardless of the directionin which the arm is moved by the stops.

KONRAD RAUCH.

